Optical sensors such as optical fiber sensors have been used in various applications including communications, optics, civil engineering and structural analysis and monitoring, and seismology. For example, it is known to use optical fiber sensors as filters in optical communications systems and as optical multiplexers and demultiplexers. Optical fiber sensors may also be utilized as strain and temperature sensing elements. These types of sensors may also be utilized for determining the presence of certain environmental elements.
As another example, optical fiber sensors may be utilized in robotic interventional systems and devices, which may be particularly well suited for use in performing minimally invasive medical procedures as opposed to conventional procedures that involve opening the patient's body to permit the surgeon's hands to access internal organs. Traditionally, surgery utilizing conventional procedures meant significant pain, long recovery times, lengthy work absences, and visible scarring. However, advances in technology have lead to significant changes in the field of medical surgery such that less invasive surgical procedures such as minimally invasive surgery (MIS) procedures are increasingly popular.
A “minimally invasive medical procedure” is generally considered a procedure that is performed by entering the body through the skin, a body cavity, or an anatomical opening utilizing small incisions rather than larger, more invasive open incisions in the body. Various medical procedures are considered to be minimally invasive including, for example, mitral and tricuspid valve procedures, patent formen ovale, atrial septal defect surgery, colon and rectal surgery, laparoscopic appendectomy, laparoscopic esophagectomy, laparoscopic hysterectomies, carotid angioplasty, vertebroplasty, endoscopic sinus surgery, thoracic surgery, donor nephrectomy, hypodermic injection, air-pressure injection, subdermal implants, endoscopy, percutaneous surgery, laparoscopic surgery, arthroscopic surgery, cryosurgery, microsurgery, biopsies, videoscope procedures, keyhole surgery, endovascular surgery, coronary catheterization, permanent spinal and brain electrodes, stereotactic surgery, and radioactivity-based medical imaging methods. With MIS, it is possible to achieve less operative trauma for the patient, reduced hospitalization time, less pain and scarring, reduced incidence of complications related to surgical trauma, lower costs, and a speedier recovery.
Special medical equipment may be used to perform MIS procedures. Typically, a surgeon inserts small tubes or ports into a patient and uses endoscopes or laparoscopes having a fiber optic camera, light source, or miniaturized surgical instruments. Without a traditional large and invasive incision, the surgeon is not able to see directly into the patient. Thus, the video camera serves as the surgeon's eyes. Images of the body interior are transmitted to an external video monitor to allow a surgeon to analyze the images, make a diagnosis, visually identify internal features, and perform surgical procedures based on the images presented to the surgeon on the monitor.
MIS procedures may involve minor surgical procedures as well as more complex operations. Such operations may involve robotic and computer technologies, which have led to improved visual magnification, electromechanical stabilization and reduced number of incisions. The integration of robotic technologies with skills of a surgeon into surgical robotics enables surgeons to perform surgical procedures in new and more effective ways.
Although MIS techniques have advanced, limitations of certain types of medical devices still have shortcomings and can be improved. For example, during a MIS procedure, catheters (e.g., a sheath catheter, a guide catheter, an ablation catheter, etc.), endoscopes or laparoscopes may be inserted into a body cavity duct or vessel. A catheter is an elongate tube that may, for example, allow for drainage or injection of fluids or provide a path for delivery of working or surgical instruments to a surgical or treatment site. In known robotic instrument systems, however, the ability to control and manipulate system components may be limited due, in part, to a surgeon not having direct access to the target site and not being able to directly handle or control the working instrument at the target site.
More particularly, MIS diagnostic and interventional operations require the surgeon to remotely approach and address the operation or target site by using instruments that are guided, manipulated and advanced through a natural body orifice such as a blood vessel, esophagus, trachea, small intestine, large intestine, urethra, or a small incision in the body of the patient. In some situations, the surgeon may approach the target site through both a natural body orifice as well as a small incision in the body.
For example, one or more catheters and other surgical instruments used to treat cardiac arrhythmias such as atrial fibrillation, are inserted through an incision at the femoral vein near the thigh or pelvic region of the patient, which is at some distance away from the operation or target site. In this example, the operation or target site for performing cardiac ablation is in the left atrium of the heart. Catheters are guided (e.g., by a guide wire, etc.) manipulated, and advanced toward the target site by way of the femoral vein to the inferior vena cava into the right atrium through the interatrial septum to the left atrium of the heart. The catheters may be used to apply cardiac ablation therapy to the left atrium of the heart to restore normal heart function.
However, controlling one or more catheters that are advanced through naturally-occurring pathways such as blood vessels or other lumens via surgically-created wounds of minimal size, or both, can be a difficult task. Remotely controlling distal portions of one or more catheters to precisely position system components to treat tissue that may lie deep within a patient, e.g., the left atrium of the heart, can also be difficult. These difficulties are due, in part, to limited control of movement and articulation of system components, associated limitations on imaging and diagnosis of target tissue, and limited abilities and difficulties of accurately determining three-dimensional positions and orientations of system components and distal portions thereof within the patient. These limitations can complicate or limit the effectiveness of surgical procedures performed using minimally invasive robotic instrument systems.
Further, the surgeon may have limited access to information or feedback (e.g., visual, tactile, etc.) to accurately advance and navigate tools such as one or more catheters, arms, shafts, etc., and position the working portions of such tools at precise locations to perform the necessary diagnostic and/or interventional procedures on the target tissue.
Electromagnetic position sensors, available from providers such as the Biosense Webster division of Johnson & Johnson, Inc., may be utilized to measure three-dimensional positions of components. While such sensors may be useful to some degree, these devices have limited utility due to, for example, hardware constraints, geometry constraints and electromagnetic radiation.